Colleges and universities nationwide could be making a big mistake by sending students home from campus because of the coronavirus. They may be making it more likely, not less, that their own students will contract the disease, and also more likely that they will spread it more widely and to populations that are more at risk.

College campuses tend to be semi-closed environments, and they are filled with people who are at an age when they are generally more robust than the general population. College students, of course, don’t spend all of their time on campus, but except for at “commuter colleges,” their lives generally revolve around campus in ways that keep them semi-segregated most of the time.